1. Field of the Invention
The present invention is broadly concerned with an improved method for obtaining starch and gluten in high yield from wheat. More particularly, it is concerned with such a method wherein starting wheat is first pearled to remove germ and bran, whereupon the pearled wheat is ground to a desired average particle size; such dry milled wheat is then subjected to wet processing in order to isolate starch and gluten fractions. Use of ground, pearled wheat results in yields of gluten on the order of 20-25% higher than obtained through the use of flour.
2. Description of the Prior Art
Of all the cereal grains, wheat is produced in largest tonnage around the world. Wheat is most often dry-milled into farina, flour, germ and bran, and those commodities are converted into food or feed. Dry-milled products are mixtures of proteins, carbohydrates, lipids, phenolics, and fiber, and their mixed composition limits their conversion to modified products. Wet-processing of wheat provides end products of singular composition, such as protein, starch, and oil. Wet-processed products from wheat, or their modified forms, may find increased use in foods, textiles, paper, and specialty products.
The two major starting materials for wet processing are the whole wheat kernel or wheat flour. Most manufacturers of gluten and starch begin with flour. If the endosperm represents 83% of the kernel, the commercial extraction of 72% flour is 11% short of ideal, and the difference is the peripheral endosperm that is high in protein. Also, milling damages some starch in the hard wheat flour.
Ideally, wheat gluten and starch would be produced starting with whole wheat kernels. Several processes have been proposed. In one process, tempered wheat is flaked and mixed into a tough hydrated dough. High-pressure water is used to wash the starch, bran and germ from the developed gluten, and then the bran and germ are screened from the starch slurry. In another process, spring hard wheat is steeped 8 hours and gently macerated mechanically to remove bran and germ from the endosperm. The endosperm then undergoes conventional processing to separate gluten and a low-grade flour. Neither of those methods are used today, probably due to high drying costs of low-value streams and/or to difficulties in obtaining high quality gluten.
There is accordingly a need in the art for an improved method for obtaining starch and gluten using whole wheat kernels as a starting material, while at the same time lowering processing costs.